Looking for patterns in eclipses: Saros series

The excitement around the 2017 Great American Eclipse shows that people are fascinated by such events. If they were not expecting such an eclipse to happen, however, it would undoubtedly be surprising and possibly even disconcerting to many people. Millennia ago, a full moon turning red over the course of a night or the blotting out of the Sun were often considered omens. Astronomers in early civilizations such as Babylonia, Mesopotamia, and China all paid note to eclipses, which were often used for the divination of earthly events. There is the possibly allegorical but often-told story of two Chinese astronomers who were beheaded for failing to predict an eclipse that occurred several thousand years BCE.